Polymers containing repeat units derived from xcex1-methylenelact(ones)(ams) such as xcex1-methylenebutyrolactones and which have reactive groups are toughened by mixing with a rubbery material which has complimentary reactive groups, or polymers containing repeat units derived from xcex1-methylenelact(ones)(ams) are toughened by mixing with polymeric core-shell particles having an elastomeric core and a specified thermoplastic shell; or blends of polymers containing repeat units derived from xcex1-methylenelact(ones)(ams) with thermoplastics often yield compositions which have a higher modulus and/or heat deflection temperature than the thermoplastic alone.
Thermoplastics comprise a large body of commercially important products. Among the uses of thermoplastics are those in which the optical properties of the polymer are important, particularly when the polymer is an optically clear material with little distortion of optical images. Such polymers, for example poly(methyl methacrylate) (PMMA) and certain polycarbonates are used as substitutes for glass where toughness is important. In uses such as for safety glazing and signage, other properties such as weather and/or heat resistance may also be important. For example if such a part needed to be thermally sterilized, it must withstand the temperature of the sterilization process. Polycarbonates often have poor weathering and/or hydrolysis resistance, while PMMA has a relatively low glass transition temperature (Tg), so its heat resistance is poor. Thus polymers with a combination of good optical properties, and heat and weathering resistance are desired.
The polymers of certain xcex1-methylenelact(ones)(ams) (AMLs) have the combination of good properties, but often are quite brittle, see for instance U.S. Pat. No. 5,880,235, and the discussion at columns 1-3, and D. Arnoldi, et al., Kunststoffe, vol. 87, p. 734-736 (1997). Thus if one could toughen these polymers without compromising their other superior properties, useful compositions would result.
While the toughening of AMLs using toughening agents is in the Applicant""s knowledge not reported in the literature, toughening of thermoplastics in general using toughening agents is known. For example, poly(meth)acrylates have been toughened by a number of methods, see for instance U.S. Pat. Nos. 5,625,001 and 5,998,554, and World Patent Application 99/12986.
Tougheners for various types of engineering resins [including (meth)acrylics] and other polymers are sold by Rohm and Haas Co., Philadelphia, Pa, U.S.A. under the tradename Paraloid(copyright), such as their EXL(trademark) series which is believe to be a core-shell polymeric particle product with a rubber core and thermoplastic shell, and also see for instance U.S. Pat. Nos. 3,678,133, 3,793,402, 3,808,180, 3,985,703, 4,180,494, and 4,543,383.
Other types of thermoplastics have been toughened by the addition of elastomeric polymers which contain reactive groups such as epoxides, see for instance U.S. Pat. No. 4,753,980.
Conversely, AMLs may be used to improve the properties of thermoplastics, including thermoplastics containing functional groups which potentially may react with the AML. Such thermoplastics include polyamides, polyesters, and polyacetals, and nonfunctional group containing thermoplastics such as styrene/acrylonitrile copolymers. It is believed that to be most effective in improving properties, the AML should be dispersed within a matrix of the thermoplastic. Polymer-polymer blends of various polymers are well known in the art, but to Applicants"" knowledge, no blends of AMLs with other polymers have been reported.
This invention concerns a first composition, comprising:
(a) a first polymer comprising the repeat units:
(i) at least about 10 mole percent of the total repeat units of 
(ii) at least about 0.1 mole percent of a repeat unit containing a first reactive functional group;
(iii) up to about 89.9 mole percent of repeat units derived from one or more monomers which are free radically copolymerizable with (a)(i) and (a)(ii); and
(b) about 1 weight percent to about 50 weight percent based on the total weight of (a) and (b), of a second polymer which is elastomeric and contains a second reactive functional group which may react with said first reactive functional group;
or
(c) a third polymer comprising the repeat units
(i) at least about 10 mole percent of the total repeat units of 
(ii) up to about 90 mole percent of repeat units derived from one or more monomers which are free radically copolymerizable with (b)(i); and
(d) about 1 percent by weight to about 60 percent by weight based on the total weight of (c) and (d), of a fourth polymer which is core-shell particles made up of an elastomeric polymer core and a polymeric thermoplastic shell, said thermoplastic shell comprising repeat units derived from methyl methacrylate
wherein:
n is 0, 1 or 2;
X is xe2x80x94Oxe2x80x94 or xe2x80x94NR9xe2x80x94; and
R1, R2, R5, R6, each of R3, and each R4, are independently hydrogen, a functional group, hydrocarbyl or substituted hydrocarbyl; and
R9 is hydrogen, hydrocarbyl or substituted hydrocarbyl.
This invention also concerns a second composition, comprising:
(e) a fifth polymer comprising the repeat units:
(i) at least about 10 mole percent of the total repeat units of 
(ii) optionally a repeat unit containing a third reactive functional group;
(iii) up to about 90 mole percent of repeat units derived from one or more monomers which are free radically copolymerizable with (e)(i), and (e)(ii), if present; and
(f) a sixth polymer which is a thermoplastic and which may optionally contain one or more fourth reactive functional groups which may react with said third functional group;
provided that in said composition (b) is present as a continuous or cocontinuous phase and (a) is present as a dispersed or cocontinuous phase;
and wherein:
n is 0, 1 or 2;
X is xe2x80x94Oxe2x80x94 or xe2x80x94NR9xe2x80x94; and
R1, R2, R5, R6, each of R3, and each R4, are independently hydrogen, a functional group, hydrocarbyl or substituted hydrocarbyl; and
R9 is hydrogen, hydrocarbyl or substituted hydrocarbyl.
Certain terms are used herein as defined below.
By xe2x80x9chydrocarbyl groupxe2x80x9d is meant a univalent group containing only carbon and hydrogen. If not otherwise stated, it is preferred that hydrocarbyl groups (and alkyl groups) herein contain 1 to about 30 carbon atoms.
By xe2x80x9csubstituted hydrocarbylxe2x80x9d is meant a hydrocarbyl group which contains one or more substituent groups which are inert under the process conditions to which the compound containing these groups is subjected. The substituent groups also do not substantially interfere with the process. If not otherwise stated, it is preferred that substituted hydrocarbyl groups herein contain 1 to about 30 carbon atoms. Included in the meaning of xe2x80x9csubstitutedxe2x80x9d are heteroaromatic rings. In substituted hydrocarbyl all of the hydrogens may be substituted, as in trifluoromethyl.
By xe2x80x9cfunctional groupxe2x80x9d is meant a group other than hydrocarbyl or substituted hydrocarbyl which is inert under the process conditions to which the compound or polymer containing the group is subjected. The functional groups also do not substantially interfere with any process described herein that the compound or polymer in which they are present may take part in. Examples of functional groups include halo (fluoro, chloro, bromo and iodo), ether such as xe2x80x94OR22 wherein R22 is hydrocarbyl or substituted hydrocarbyl.
By xe2x80x9creactive functional groupxe2x80x9d is meant a functional group that may react with another functional group present in the process or composition. By xe2x80x9cmay reactxe2x80x9d is meant that the functional group may react with its counterpart reactive group, but it is not necessary that such reaction happen or that all of the reactive functional groups react with one another. Usually in the formation of the compositions described herein some fraction of these reactive functional groups will react.
By xe2x80x9ccopolymerizable under free radical conditionsxe2x80x9d is meant that the (potential) monomers, preferably vinyl monomers, involved are known to copolymerize under free radical polymerization conditions. The free radicals may be generated by any of the usual processes, for example thermally from radical initiators such as peroxides or azonitriles, by UV radiation using appropriate sensitizers, and by ionizing radiation. The copolymerization may be done in any number of known ways, for example bulk, solution, suspension, or aqueous suspension or emulsion, or combinations of methods such as bulk-suspension. These polymers may be prepared by various types of processes, such as continuous, batch and semibatch, which are well known in the art. Many combinations of free radically copolymerizable monomers are known, see for instance J. Brandrup, et al., Ed., Polymer Handbook, 4th Ed., John Wiley and Sons, New York, 1999, p. II/181-II/308.
By xe2x80x9celastomeric or rubbery polymerxe2x80x9d is meant a polymer having a flexural modulus (of unfilled pure elastomeric polymer) of 35 MPa or less when measured by ASTM D790, and not having a Tg above 30xc2x0 C., preferably not having a Tg above 0xc2x0 C. Glass transition temperatures are measured by ASTM D3418 at a heating rate of 20xc2x0 C./min and the Tg is taken as the midpoint of the transition.
In the first, third and fifth polymers herein, (I) is present as a repeat unit. (I) is derived from the monomer 
wherein X and R1 through R6 and R9 are as defined above. In preferred structures (I) and (III):
n is 0; and/or
R1, R2, R3, R4, R5 and R6 are hydrogen or alkyl containing 1 to 6 carbon atoms, more preferably all are hydrogen; and/or
X is xe2x80x94Oxe2x80x94 or xe2x80x94NR9xe2x80x94 wherein R9 is hydrogen or alkyl containing 1 to 6 carbon atoms, more preferably X is xe2x80x94Oxe2x80x94.
In particularly preferred structures for (I) and (III), n is 0, X is xe2x80x94Oxe2x80x94 and R1, R2, R5 and R6 are hydrogen, or n is 0, X is xe2x80x94Oxe2x80x94, R6 is methyl, and R1, R2 and R5 are hydrogen. For other preferred structures of (I) and (III) see U.S. Pat. No. 5,880,235, which is hereby included by reference, at column 4, line 44 to column 8, line 59.
In the first polymer (I) is at least about 10 mole percent of the repeat units present, preferably at least about 20 mole percent, more preferably at least about 50 mole percent. The repeat unit (a)(ii) in the first polymer has a functional group which is reactive (with a functional group in the second polymer). Useful functional groups in repeat unit (a)(ii) are epoxy, carboxylic anhydride, isocyanato, hydroxyl, carboxyl, and primary and secondary amino. Repeat units containing these functional groups may be derived from maleic acid or anhydride (for carboxylic anhydride) or from functional (meth)acrylates of the formula 
wherein R13 is hydrogen or methyl and Z may be (for example) xe2x80x94OH, xe2x80x94OCH2CH2OH, xe2x80x94N(CH3)CH2CH2NH2, and 
In a preferred repeat unit (a)(ii) Z is xe2x80x94OH (acrylic or methacrylic acid) and it is even more preferred if R13 is methyl (methacrylic acid). Preferably the level of repeat unit (a)(ii) is about 0.1 to about 25 mole percent, more preferably about 1 to about 10 mole percent, of the total repeat units. In another preferred repeat unit (a)(ii) Z is xe2x80x94CH2CH2OH (2-hydroxyethyl methacrylate or 2-hydroxyethyl acrylate), more preferably in this compound R13 is methyl (2-hydroxyethyl methacrylate).
In the fifth polymer a repeat unit (e)(ii) containing a third reactive functional group may be present. This repeat unit may be derived from monomers listed above for repeat unit (a)(ii), and be present at the same levels preferred for (a)(ii). It is also to be noted that in the fifth polymer it is possible that repeat units derived from (I) may also react with the fourth functional group. These are not considered to be repeat unit of the type (e)(ii) but of type (e)(i). For example the lactone ring of a (e)(i) may open and react with a functional group of (e)(iii).
In the first, third and fifth polymers additional repeat units (a)(iii), (c)(ii), and (e)(iii), respectively, may also be present. Preferably these repeat units have the formula 
wherein R14 is hydrogen or methyl, and R15 is hydrocarbyl or substituted hydrocarbyl, preferably alkyl, and R16 is hydrogen or methyl and R17, R18, R19, R20 and R21 are each independently hydrogen, hydrocarbyl substituted hydrocarbyl or a functional group. In a preferred structure (V) R14 and R15 are both methyl (methyl methacrylate), and in a preferred structure (VI) R16, R17, R18, R19, R20 and R21 are all hydrogen (styrene).
In a particularly preferred first or fifth polymer, 0 to about 40 mole percent of the repeat units present are derived from methyl methacrylate, and 0 to about 5 mole percent of the repeat units are derived from an alkyl acrylate wherein the alkyl group has 2-4 carbon atoms, more preferably ethyl acrylate or n-butyl acrylate. In a particularly preferred third polymer, 0 to about 40 mole percent of the repeat units present are derived from methyl methacrylate, and 0 to about 5 mole percent of the repeat units are derived from an alkyl acrylate wherein the alkyl group has 2-4 carbon atoms, more preferably ethyl acrylate or n-butyl acrylate. The second polymer is elastomeric, or a core-shell polymer wherein the second reactive functional group is in the shell portion of the polymer, and amount of functional as described below refer to the amount of second functional group in the core portion of the core-shell polymer only. The core-shell polymers are similar to those described below for the fourth polymer, except have a functional group in the shell. Such functional groups may be incorporated for example by copolymerizing a functional monomer such as a hydroxyethyl (meth)acrylate or glycidyl (meth) acrylate into the shell. Preferably the shell of this core-shell polymer also comprises repeat units derived from methyl methacrylate.
Generally speaking the first, third and fifth polymers may be mixed in any proportion with one or more other type(s) of polymer(s) to form a polymer blend. The other polymer(s) may be an elastomer (with or without functional groups), and/or a thermoplastic. The elastomer may or may not be crosslinked. It is preferred that in such blends there be a continuous phase and a dispersed phase. Depending on the composition of the blend and its desired properties, the first third or fifth polymers may be the dispersed or continuous phases, and the other polymer(s) present would be in the complementary phase. Preferably the first third and fifth polymers are 1 to 99 volume percent of the blend and the other polymer(s) are 99 to 1 volume percent of the blend. Preferred first third and fifth polymers for these general types of blends are the same as described above for the first third and fifth polymers.
The second polymer has a second reactive functional group which may react with the first reactive functional group of the first polymer. Table 1 below gives some useful functional groups and some of the corresponding functional groups with which they may react. Either functional group of these reactive pairs may be present in the first polymer and the other functional group present in second polymer.
In one particularly preferred combination of first and second polymers the first polymer contains carboxyl or hydroxyl groups, especially preferably derived from methacrylic acid, in the case of carboxyl groups, and from a hydroxyalkyl (meth)acrylate, especially 2-hydroxyethyl methacrylate, in the case of hydroxy groups, and the second polymer contains epoxy groups. A particularly preferred second polymer is an elastomeric copolymer of ethylene, an alkyl (particularly those having 1-8 carbon atoms) acrylate and glycidyl acrylate or methacrylate, particularly glycidyl methacrylate. Such copolymers are described in U.S. Pat. No. 4,753,980, which is hereby included by reference. For example such a copolymer may contain 40-90 weight percent ethylene repeat units, 10-40 weight percent of an alkyl acrylate or methacrylate, and 0.5-20 weight percent of glycidyl acrylate or methacrylate. Another type of second polymer which is useful is an elastomeric polymer on which a compound containing an appropriate functional group has been grafted, for example an ethylene/propylene (EP) or ethylene/propylene/diene (EPDM) rubber grafted with maleic anhydride. Preferably the second polymer contains about 0.01 to about 1.5 moles, more preferably about 0.03 moles to about 1.0 moles of the second reactive group per kg of second polymer.
The fourth polymer is in the form of so-called core-shell particles. These are polymer particles, often made in suspension or emulsion polymerization, which have a core of one polymer, and a shell (outer layer) of another polymer. These polymers are well known, and known to be useful for the toughening of various thermoplastics, see for instance U.S. Pat. Nos. 3,678,133, 3,793,402, 3,808,180, 3,985,703, 4,180,494, and 4,543,383, all of which are hereby included by reference. For the elastomeric core various types of elastomers may be used, for example poly-1,3-butadiene, poly(meth)acrylic esters and their various copolymers, EPDM, and other polymers. Preferred core materials are poly(1,3-butadiene-co-styrene), and various elastomeric acrylate copolymers, for example those containing one or more of ethyl acrylate, n-butyl acrylate, and 2-ethylhexyl acrylate. For the thermoplastic shell various (meth)acrylic polymers may be used, but poly(meth)acrylic esters and their copolymers are preferred. A preferred shell material is PMMA or a copolymer of methyl methacrylate which is at least 50 weight percent methyl methacrylate. The core and/or shell may be crosslinked in various ways, for example by using difunctional monomers in relatively small amounts to form crosslinks. It is preferred that the shell portion of the particle be relatively thin, so that at least about 50 percent by volume of the average particle is elastomeric (core) polymer.
The sixth polymer may have fourth functional groups which are complimentary to the third reactive functional groups, in an analogous manner to the first and second reactive functional groups above.
Polymers containing (I) may be made by the free radical (co)polymerization of (III), see for instance U.S. Pat. No. 5,880,235 and references cited therein. When (I) is present in a copolymer, it tends to raise the Tg of most copolymers. For example in a copolymer of (III) with methyl methacrylate, the Tg will normally be above the Tg of a PMMA homopolymer.
In the first composition some of the toughened polymers described herein are transparent when visually viewed, see for instance Examples 2 and 5. It is believed the toughening agents used in these examples have refractive indices very close to the polymer being toughened.
When the two (or more) polymers of the first composition are mixed, it is preferred that the second polymer be uniformly dispersed in the first polymer, or the fourth polymer be uniformly dispersed in the third polymer. It is preferred that the discontinuous phase (second or fourth polymers) be of relatively small particle size, typically in the range of 0.01-10 xcexcm. This can be achieved in high shear melt mixers such as single and especially twin-screw extruders, or other types of melt mixers.
In the second composition herein a sixth polymer, a thermoplastic, is present in a blend with a fifth polymer, which is a homo- or copolymer of (I), preferably a copolymer of (I). By xe2x80x9cthermoplasticxe2x80x9d is meant the usual meaning, a polymer which contains crystallites at 30xc2x0 C. which have a heat of fusion of 1 J/g or more, or whose glass transition temperature is greater than 30xc2x0 C. when measured by ASTM D3418 at a heating rate of 20xc2x0 C./min and the Tg is taken as the midpoint of the transition. Useful thermoplastics include polyesters such as poly(ethylene terephthalate) and poly(butylene terephthalate), polyamides such as nylon-6,6 and nylon-6, polyolefins such as polyethylene and polypropylene, liquid crystalline polymers including polyesters and poly(ester-amides), other vinyl addition polymers such as polystyrene and poly(styrene-co-acrylonitrile), polyacetals, polycarbonates and poly(meth)acrylates such as poly(methyl methacrylate). Preferred sixth polymers are polyamides, especially nylon-6 and nylon-6,6, polyester, especially poly(ethylene terephthalate) and poly(butylene terephthalate), and polyacetals especially polyoxymethylene. In the second composition the fifth polymer is preferably present as dispersed particles. The sixth polymer is preferably present as a continuous phase. This phase relationship is most readily obtained when the major portion of the polymer blend by volume is the sixth polymer and the minor portion is the fifth polymer (based on the total volume of fifth and sixth polymers present). Preferably the fifth polymer is about 5 to about 70 weight percent. More preferably, from about 20 to about 50 weight percent.
The second composition can be most readily made by melt mixing the fifth and sixth polymers in an apparatus such as a single or twin screw extruder that imparts sufficient shear to the mixture to disperse the fifth polymer in the sixth polymer. It is believed that this dispersion takes place in many instances relatively easily compared to making other similar polymer blends because the fifth polymer (whether or not it contains deliberately introduced reactive functional groups) reacts with many of the sixth polymers which may be used, for example by opening of some of the lactone rings.
All of the compositions herein may additionally comprise other materials commonly found in thermoplastic compositions, such as fillers, reinforcing agents, dyes, pigments, antioxidants, and antiozonants. These materials may be present in conventional amounts, which vary according to the type(s) of material(s) being added and their purpose in being added.